Verification

Test	At three jobs that allow regrind, put an empty bin at the press for one shift. Only runners and rejected parts go into it. At the end of the shift, weigh each bin on the floor scale, less the empty bin, and write down the job, the plastic and the pounds.
Cost	About $45 of a material handler's time: about 90 minutes spread over one shift, at $30 per hour. Nothing is bought.
Duration	One shift
Confirmed if	The three bins together weigh about 25 pounds or more. Over a year of shifts that is the 6,250 pounds per grinder this card counts.
Ruled out if	The three bins together weigh under about 4 pounds. A grinder would then not cover what it costs to run. In between, a grinder pays back more slowly than we count.